The rail industry needs lightweight materials and structures for rail vehicles in order to meet the challenges it faces in terms of capacity increases and energy efficiency. Lightweighting also brings reductions in vehicle operating costs. Furthermore, lighter vehicles cause less damage to track, thereby reducing infrastructure renewal costs.
A railway vehicle defining a longitudinal direction and comprising: a central section and a modular vehicle cabin is disclosed in WO 05/085032. The vehicle cabin comprising a collapsible front section that undergoes controlled collapse in case of collision and at least one rigid section located between the front section and the central section. The front section has a lower resistance to deformation than the rigid section. At least one dedicated repair interface is provided for removably fixing the vehicle cabin to the central section. The dedicated repair interface comprises a thick sheet metal plate extending in a vertical plane perpendicular to the longitudinal direction over the whole cross-section of the vehicle body with or without opening for allowing access from the vehicle cabin to the central section of the vehicle. The vehicle cabin has a self-supporting and deformation-resistant modular structure providing a driver space and a windshield opening. This cabin structure is composed of frame members made of steel and comprises side pillars each having a lower end and an upper end, and an undercarriage structure at the lower end of each of the side pillars. Such rail vehicle cab structures based on welded steel assemblies including an additional composite cover can weigh more than 1 tonne each. With two cabs per train-set, this represents a significant weight saving opportunity. Furthermore, current cab designs tend to be very complex, high part count assemblies with fragmented material usage. This is because they must meet a wide range of demands including proof loadings, crashworthiness, missile protection, aerodynamics and insulation. Assembly costs are high, and there is little in the way of functional integration.
A rail vehicle provided with a head module made of a fibre composite material is known from U.S. Pat. No. 6,431,083. The undercarriage of the vehicle supports the coach body of the vehicle and extends beyond the coach body to support the head module, which is joined to the undercarriage via a nearly horizontal interface. The head module consists of at least one head module front wall, two head module side walls, and one head module roof, which can be produced jointly as one unit. While the assembly of the head module on the undercarriage is simple and allows a certain degree of modularity in the design of the vehicle, its replacement in case of a front collision is much more difficult, since the undercarriage is not part of the head module and is likely to be damaged during the crash. Moreover, only partial weight reduction is achieved since the undercarriage is a conventional cast or welded metal structure. Last but not least, the unitary structure of the head module is a uniform sandwich structure composed of a core and laminated walls, which are not locally optimised for selectively dissipating, i.e. absorbing, the impact energy that occurs during a crash while preserving a survival space for the driver. A similar design with similar same limitations is disclosed in EP 0 533 582, which relates to a modular driver's cabin to be attached on the undercarriage of a rail vehicle. The walls of the cabin constitute a one-piece assembly including a front wall a bottom, a roof, a rear wall and two sidewalls. The wall of the cab and the framework of the cab console constitute a one-piece composite material assembly. The integration of the console framework stiffens the cab.
A vehicle front end module comprising both an undercarriage structure and wholly composed of structural elements made from fibre composite or fibre composite sandwich material is disclosed in US 2010/0064931. By using different composite/fibre composite sandwich structures for the individual areas of the vehicle front end module structure, it becomes conceivable to provide both a substantially deformation-resistant, self-supporting structure composed of first structural elements made of fibre-reinforced polymer (FRP), which does not collapse upon collision thereby providing a survival space for the driver, and an impact absorbing structure located in front of the deformation-resistant structure and composed of second structural elements designed to at least partly absorb the impact energy. The highly rigid first individual structural elements building the deformation-resistant, self-supporting structure include A pillars, side struts, a railing element to structurally connect the two A pillars and the two side struts, and an undercarriage structure, which have to be connected together, preferably in a material fit and more specifically an adhesive bond. The number of individual parts of the front end assembly is therefore high, hence a high manufacturing cost. Due to dimensional tolerances and manufacturing limits, the material fit between the individual parts may be imprecise. Moreover, the interface between individual structural elements is less than optimal in terms of mechanical behaviour, reproducibility, additional weight and thermal and acoustic isolation.